1. Field of the Invention
The present invention generally relates to an optical scanning device, an image forming apparatus, and an optical scanning method.
2. Description of the Related Art
In order to improve responsiveness of a light source in response to an instruction of a control signal (also known as and hereinafter simplified as “responsiveness”), there is a known method in which a weak current is kept flowing through the light source (also known as and hereinafter referred to as a “bias current”) so that the light source emits weak light.
In this regard, in order to supply a stable gradation, there is a known method in which the bias current is controlled based on a light emission amount of the light source (see, for example, Japanese Laid-open Patent Publication No. 2004-268436).
Further, in order to reduce the temperature difference between the light sources, there is known a method in which the light source is emitted in a non-effective scanning period (see, for example, Japanese Laid-open Patent Publication No. 2000-118041).